JPS5933211Y2 - Tractor three-point hitch - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a three-point linkage device for connecting a working machine to a tractor, and its purpose is to prevent rattling of a top link hitch.

Conventionally, the top link hitch was attached to the top link hinge with bolts, so looseness was likely to occur between the two.
Therefore, it is easy to loosen, it takes time to install, and it is difficult to install.

The present invention solves the above-mentioned conventional problems by constantly pressing the two cylindrical hinge bosses provided on the top link hitch in a direction perpendicular to the hinge pin by means of a tension cam that is fitted over the two cylindrical hinge bosses and receives the elasticity of a spring. This problem will be explained next using the drawings.

FIG. 1 is a partial left side view (arrow F points toward the front) showing a part of the agricultural tractor to which the present invention is cut away, in which the PTO shaft 2 protruding rearward from the rear surface of the rear axle case 1 is Connect to the gear case 5 of the rotary 4,
The gear case 5 and the rear axle case 1 are connected by a pair of left and right lower links 6 and one top link 7 (three-point link).

The rear end of the top link 7 is connected to the gear case 5 via an upper arm 8, and the front end is connected to the top link hinge 1 via a top link hitch 9 and two upper and lower pins 10, 10a.
Connected to 1.

The top link hinge 11 is fixed to the rear surface of the hydraulic cylinder 12 on the rear axle case 1, and a pair of left and right lift arms 13 protrude rearward from the hydraulic cylinder 12, and the rear end of each lift arm 13 connects to a lift link 14. It is connected to the lower link 6 on the same side via the lower link 6 on the same side.

The rear axle case 1 is connected to the engine via the transmission case and clutch housing, and therefore, a part of the engine's rotational force is transmitted from the PTO shaft 2 to the drive shaft 3 and the gear case 5 to the rotary 4, which performs tilling work. It can be carried out.

Further, when the lift arm 13 is raised by a hydraulic control lever (not shown), the movement of the lift arm 13 is transmitted to the lower link 6 through the lift link 14, and the rotary 4 can be lifted.

Figure 2 is a partially enlarged view of Figure 1, Figure 3 is M-1 in Figure 2.
As is clear from the cross-sectional view, especially in FIG.
A pin 10 is fitted inside, both ends of the pin 10 are fitted into holes 19 of two side plates 18 of the top link hinge 11, and the tip of the pin 10 protruding from one side plate 18 is provided with a retainer. The pine needle pin 20 is used for attachment.

The same applies to the supporting rock structure of the lower hinge boss 17a.

Arc-shaped cam surfaces 23, 23a of rectangular tension cams 22, 22a are pressed against the seat 21 of the top link hinge 11 by the elasticity of a torsion coil spring 24.

The cam 22 is located at the hole 25 of the middle shaft, and the side plates are 16°16
The coil spring 24 is rotatably fitted onto the hinge boss 17 between the coil springs 24 and 24, and one end of the coil spring 24 is latched into a hole 26 provided on the side surface near the cam surface 23.

As is clear from FIG. 2, the cam surface 23a of the lower cam 22a is in pressure contact with the seat 21 in an attitude that is approximately symmetrical to the cam 22 with respect to the horizontal plane O-O, and the coil is inserted into the hole 26a of the cam 22a. The lower end of the spring 24 is latched, so when the top link hit device is shown in solid line in FIG. 2, the upper and lower cams 22,
22a is urged in the expansion direction by the elasticity of the coil spring 24, and the cam surfaces 23, 23a are pressed against the seat 21 and receive reaction forces F and Fa from the seat 21, so that the cam surface 22a protrudes at a substantially right angle to the seat 21. It plays the role of upholstery.

That is, the upper cam 22 applies a force in the direction of arrow F to the hinge boss 17 at the hole 25 portion, and therefore the hinge boss 17 applies a force in the same direction to the pin 10, thereby causing play between the cam 22 and the hinge boss 17, The play between the hinge boss 17 and the pin 10 and the play between the pin 10 and the hole 19 are always eliminated by the tensioning action of the cam 22.

The same applies to the lower cam 22a portion.

When removing the top link hitch 9, for example, remove the upper cam 2.
A force in the direction of arrow A is applied to the handle portion 27 of No. 2 to rotate the cam 22 against the elasticity of the coil spring 24.

Then, after the upper end of the coil spring 24 (the part that fits into the hole 26) passes the point on the line 28 connecting the pin 10 and the hole 26a, it automatically moves in the direction of arrow A due to the elasticity of the coil spring 24. When the coil spring 24 is in a free state, the cam 2
2 occupies the position 22' rotated approximately 180'liC, the lower cam 22a also assumes the 22a' (7) position, and both seat 21
move away from

Therefore, the upper and lower pins 10, 10a are not subjected to any force in the right angle direction and can be easily removed.

When attaching the top link hitch 9 to the top link hinge 11, the cams 22.22a are aligned with the two-dot chain lines 22', 2.
2'a, insert the upper and lower pins 10, 10a, and then turn the upper cam 22' about 1800 times in the opposite direction A against the elasticity of the coil spring 24.
The cam surface 23.23a of 2.22a is pressed against the seat 21 in the expansion direction by the elasticity of the coil spring 24, and can be used as a tension member.

(Effect of the invention) Two upper and lower parallel cylindrical hinge bosses 17, 17a provided on the top link hitch 9 are attached to the top link hinge 11 via two pins 10° 10a, and each hinge boss 1
7, 17a, the tension cam 22° 22a is rotatably fitted, and the seat 21 of the top link hinge 11 and the pin 10, 10a are fitted.
Both ends of substantially dogleg-shaped torsion coil springs 24 are locked to the two tension cams 22 and 22a between the two tension cams 22 and 22a so as to be rotatable about the center line parallel to the pins 10 and 10a. By contracting the torsion coil spring 24 in an open position toward the seat 21 side, the tension cams 22, 22
a is elastically pressed against the seat 21 of the top link hinge 11 to prevent the top link hit 9 from rattling and to release the cam 22.22a while the cam 22.22a is engaged with the top link hit 9. (a) By simply rotating the cam 22 or cam 22a or pulling the coil spring 24, the seat 21 of the cam 22 and 22a can be easily moved with one touch.
The pressing force against can be released at once.

Also, when the cams 22, 22a are pressed against the seat 21, the operation is extremely simple, as the cam 22 may be rotated in the opposite manner.

(b) A tension cam 22 is attached to each hinge boss 17, 17a.
Since the structure is such that the cam 22, 22a is rotatably fitted, there is no risk of the cam 22, 22a popping out when attaching or removing the cams 22, 22a, or losing the cam 22, 22a during use. do not have.

Also, since the cams 22 and 22a are always attached to the hitch 9, when the hitch 9 is attached to the hinge 11, the cams 22 and 22a are always attached to the hitch 9.
There is no fear of forgetting to attach the 22a.

Moreover, since there is no need to provide a special pin for the cams 22, 22a, the structure is not only simple, but the hitch 9 can be mounted closer to the seat 21.
The strength of the installation is critical.

[Brief explanation of drawings]

Figure 1 is a partial left side view with a part cut away of an agricultural tractor to which the present invention is applied, number 2 is a partially enlarged view of Figure 1, and Figure 3 is a 1-1 sectional view of Figure 2. . 9...Top link hit, 10,10a...
...Pin, 11...Top link hinge,
17, 17a... Cylindrical hinge boss, 21...
... Seat, 22, 22a... Tension cam.

Claims (1)

[Scope of utility model registration request] Two upper and lower parallel cylindrical hinge bosses 17, 17a provided on the top link hitch 9 are attached to the top link hinge 11 via two pins 10° 10a, and each hinge boss 1
7, 17a, the tension cam 22° 22a is rotatably fitted to the seat 21 of the top link hinge 11 and the pin 10, 10a.
Both ends of substantially dogleg-shaped torsion coil springs 24 are locked to the two tension cams 22 and 22a between the two tension cams 22 and 22a so as to be rotatable about the center line parallel to the pins 10 and 10a. By contracting the torsion coil spring 24 in an open position toward the seat 21 side, the tension cam 22.22
a is elastically pressed against the seat 21 of the top link hinge 11 to prevent the top link hit 9 from rattling, and also to release the cams 22 and 22a while the cams 22 and 22a are engaged with the top link hit 9. A three-point linkage device for a tractor, characterized by: